Kothari Dhwani J, Davis Mary C, Yeung Ellen W, Tennen Howard A
Department of Psychology, Arizona State University, Tempe, AZ, USA Department of Community Medicine and Health Care, University of Connecticut Health Center, Farmington, CT, USA.
Pain. 2015 Mar;156(3):540-546. doi: 10.1097/01.j.pain.0000460324.18138.0a.
Fibromyalgia (FM) is a chronic pain condition often resulting in functional impairments. Nonrestorative sleep is a prominent symptom of FM that is related to disability, but the day-to-day mechanisms relating the prior night's sleep quality to next-day reports of disability have not been examined. This study examined the within-day relations among early-morning reports of sleep quality last night, late-morning reports of pain and positive and negative affect, and end-of-day reports of activity interference. Specifically, we tested whether pain, positive affect, and negative affect mediated the association between sleep quality and subsequent activity interference. Data were drawn from electronic diary reports collected from 220 patients with FM for 21 consecutive days. The direct and mediated effects at the within-person level were estimated with multilevel structural equation modeling. Results showed that pain and positive affect mediated the relation between sleep quality and activity interference. Early-morning reports of poor sleep quality last night predicted elevated levels of pain and lower levels of positive affect at late-morning, which, in turn, predicted elevated end-of-day activity interference. Of note, positive affect was a stronger mediator than pain and negative affect was not a significant mediator. In summary, the findings identify 2 parallel mechanisms, pain and positive affect, through which the prior night's sleep quality predicts disability the next day in patients with FM. Furthermore, results highlight the potential utility of boosting positive affect after a poor night's sleep as one means of preserving daily function in FM.
纤维肌痛（FM）是一种慢性疼痛疾病，常导致功能障碍。非恢复性睡眠是FM的一个突出症状，与残疾相关，但前一晚睡眠质量与次日残疾报告之间的日常机制尚未得到研究。本研究考察了日内关系，即昨晚清晨睡眠质量报告、上午晚些时候疼痛及正负性情绪报告与当日结束时活动干扰报告之间的关系。具体而言，我们测试了疼痛、正性情绪和负性情绪是否介导了睡眠质量与随后活动干扰之间的关联。数据来自220名FM患者连续21天收集的电子日记报告。采用多水平结构方程模型估计个体水平上的直接效应和中介效应。结果表明，疼痛和正性情绪介导了睡眠质量与活动干扰之间的关系。昨晚清晨睡眠质量差的报告预示上午晚些时候疼痛水平升高和正性情绪水平降低，而这反过来又预示当日结束时活动干扰增加。值得注意的是，正性情绪比疼痛是更强的中介因素，负性情绪不是显著的中介因素。总之，研究结果确定了两种并行机制，即疼痛和正性情绪，通过这两种机制前一晚的睡眠质量可预测FM患者次日的残疾情况。此外，研究结果凸显了在睡眠不佳后提升正性情绪作为维持FM患者日常功能的一种手段的潜在效用。
